mysterious deaths

[vafa]

in the past 2-4 weeks 3 neon tetra's died.
all showed no signs of illness.
didn't act strange in any way/
my parameters are
ammonia 0
nitrite 0
nitrate 40
the nitrate really shocked me. i use to to 33% water changes and never got a nitrate rating higher then 10-20 in this tank. lately i have been doing 50% and then my nitrates show 40?
there is no nitrate in the tap either. but i did recently remove a ton of algae which could have took my nitrates down a notch. i did add a amazon sword plant right after i did that though.
regardless i don't think the nitrates killed my neons. they would have shown signs of stress. all my other fish are fine too.
could it be some kind of internal parasite? bad luck?
maybe my ram stresses them out. i only say that because for the first time ever i saw my ram try to nip a neon a week ago. but i had this tank for a year and have never seen him do that.
my neons are 6 months - 1 year old depending on when i got them. i think that rules out old age. thoughts?

[KevinVA]

40 nitrates is pretty high and neons aren't the most hardy species, either. I would suggest that some of the weaker ones succumbed to the rising level of toxins, which was an abnormality for your tank. Algae does eat up a lot of nitrates, so that's probably why you're seeing a spike. That might be a sign that you're overfeeding your tank. Swords won't absorb a lot of nitrates, because they're slow growers and gain most of their nutrients from the substrate - not the water column.

Have you thought about adding a moss ball? That should help, but in the meantime, when was the last time you cleaned your filter out? It could be pretty nasty in there, which could account for the higher nitrate count.

[vafa]

damn, it has been a while since i've cleaned out my filter (6+ months) oops.
and i have been under feeding my tank for my holiday break. the only reason is because i'm here for a few days and then im there for a few days. tommorow i will get my nitrates down to 10.
why didn't they show signs of stress. then i could of saved them quite easily

[Cermet]

Also, once a high nitrate begins to show, the substrate if often saturated with the waste. Consider also stiring the substrate just before a 75%+ water change. While Neon's really require very clean water (nitrates under 5 ppm and under 2 ppm better still) NO fish should endure nitrates of 40 ppm - that is getting toxic. Nitrates are a toxic waste - far too many people think that the final bio-filter waste is non-toxic and of little worry - that is a very incorrect belief. Nitrates should be as low as possible. Fish can tolerate values above 10 ppm but that isn't the same as it being 'safe'. It is a damaging waste.

[Cliff]

I would suggest cleaning your filter with tank water and a deep gravel vac of all of your substrate.

Check your nitrates every few days and adjust your water change amounts from there

[mommy1]

Don't stir up the substrate. Stick the siphon straight in the gravel and leave it there until the water starts to come up clean, then pick the siphon straight out and keep going this way. Stirring up the gunk that is in the gravel will release more toxins into the water column.

[vafa]

should i replace my sponge filter media?

[Slaphppy7]

Only replace the sponge if it is falling apart, otherwise squeeze it out a bunch of times in old tank water.

[KevinVA]

should i replace my sponge filter media?

It's not necessary to replace it. You can use it until it begins falling apart. Rinse it under the tap and make sure you squeeze out the junk. If it's been 6 months, it'll probably be really nasty. Just keep squeezing it out until the water that flows through it is clear. When you're done, squeeze out the excess water and throw it in the filter again.

[Stlouisfish]

Nah - I also went for quite some time before cleaning my filter - even though the sponges were pretty gross/gray, etc. - I used about 4-5 buckets of tank water to squeeze them out and they are in decent shape (I've had them 3 yrs - I have 4 of them).

If you have more than 1 and you desire to put a new one in there, replace one at a time and wait until the next filter cleaning to replace the next one.